Collating machines accumulate documents, for example, burst or cut documents from a continuous, perforated web which is fed into the machine and guided towards a path for further processing, such as folding and insertion into envelopes. In inserter systems, such as the Pitney Bowes 8300 Series Inserters, collating machines are used in-line with other paper handling equipment as a means of assembling a plurality of sheets of paper into a particular, desired packet prior to further processing, which may include additional collating, folding and inserting. In a typical paper handling sequence involving an initial output consisting of a plurality of sheets of paper, to be later combined with subsequent output from other sheet feeding devices situated downstream, the initial output is fed from a first feeding device, for example, a burster or cutter, seriatim to the collator, which collates the output into desired packets. Each packet may then be folded, stitched or subsequently combined with other output from document feeding devices located downstream thereof and ultimately inserted into a mailing envelope. For further background, reference can be made to U.S. Pat. Nos. 3,935,429, 4,547,856 and 4,733,359.
Examples of collating machines used in inserter systems are disclosed in U.S. Pat. Nos. 4,805,841 and 4,640,506 which disclose collators having the capability to collate in standard or reverse order. Collating machines are also disclosed in U.S. Pat. Nos. 4,799,663, 4,925,180 and 4,925,362. The collating machines disclosed in the aforementioned patents use an upper and lower belt and pulley configuration to convey sheets into and collations out of the collating machine. Stop/registration wheels are used to stop the forward progress of the sheets being accumulated to form the collation. The stop/registration wheels are wheels which have a section cut out to provide a flat vertical surface which abuts a flat horizontal surface for stopping and aligning the leading edge of the sheets to form a collation. When the last sheet of a collation is accumulated, the stop/registration wheels rotate towards the downstream direction so that the belts can remove the collation.
An inherent problem with the aforementioned collating machines is that the lead edge alignment is not maintained as the collation is removed from the collating machine The stop/registration wheels have been found to be unsuitable for maintaining lead edge alignment when the wheels rotate as the collation is removed from the collating machine.
The operation of the aforementioned collating machines deteriorates as the size of a collation increases. Typically, problems are encountered relating to controlling large collations as they are removed from the collating machine. Although the belt and pulley configuration is suitable for conveying sheets to form a collation and for removing a small collation, for example of five to seven sheets, the belt and pulley configuration is not suited for handling large collations. For collations of fifteen or more sheets, the belt and pulley configuration loses control of the collation as it is removed resulting in shingling or stalling the machine.
The stop/registration wheels employed in the aforementioned collating machines have proved to be unsuitable for maintaining lead edge alignment as the collation is removed. As a solution to this problem, the stop/registration wheels were eliminated and upper and lower pinch rollers were added to serve the twofold purpose of stops and drive rollers. The pinch rollers were situated at the downstream end of the belt and pulley configuration. The advancing sheets being collated were stopped at the nip of the pinch rollers. This caused the lead edge of the collation to be shingled as the sheets were accumulated. When the collation was to be removed from the collation stack area, the pinch rollers were actuated via a clutch mechanism to drive the collation out. As the drive rollers were actuated, the upper rollers pivoted up to allow the collation to pass. Although this structure works well for accumulating collations of up to fifteen sheets, it is not suitable for larger collations. Furthermore, this structure requires that lead edge alignment of the collation be performed downstream from the collating machine.
In U.S. Pat. No. 4,621,966, there is shown a shingle compensating device used in a collation machine whereby the collation is removed from the collating machine by a first and second pair of feed rollers with one pair of feed rollers acting as a positive drive and the second pair of feed rollers acting as the alignment mechanism. This collating device does not provide a lead edge alignment mechanism, but teaches the intentional shingling the leading edges of the collated material so that they can be later aligned in a buckle chute folding device.
Each of the aforementioned collating machines requires a means for aligning the leading edges of the collation downstream from the collating machine because of the lack of control of the sheets leaving the collator or because of the problems associated with aligning the mechanism in the nip of the downstream belts and pulleys of the collating machine. Accordingly, the present invention provides a collating machine with an alignment mechanism that aligns the collated sheets as the collation is formed and a device for better controlling the documents as the collation is removed from the collating machine.